1. Field of the Invention
The present invention relates to a silicon light-emitting device having circuits required for driving radiation and a display device employing the silicon light-emitting device. The present application is based on Korean Patent Application No. 2002-12157, filed Mar. 7, 2002.
2. Description of the Related Art
Silicon semiconductor substrates can be highly integrated with logic circuits, arithmetic circuits, and drive devices with high reliability. Because silicon is inexpensive, highly integrated circuits using silicon can be obtained at a much lower cost than when using a compound semiconductor. Accordingly, most integrated circuits use silicon (Si) as their fundamental material.
Due to the indirect transition bandgap of silicon, it is difficult for light emission to occur in silicon. Accordingly, a light-emitting device, such as a light emitting diode (LED), is made of a compound semiconductor material that has a direct transition bandgap and contributes to light emission.
A light-emitting device emits light only when it is subjected to current higher than a critical current. Hence, in order to supply appropriate current to light-emitting devices, amplification circuits for amplifying low current into current suitable to oscillate the light-emitting devices, and/or switching circuits for controlling a light-emitting on-off operation, are typically required.
However, due to a hybrid junction, compound semiconductor light-emitting devices cannot be combined with silicon-based amplification circuits and/or silicon-based switching circuits through a series of semiconductor manufacturing processes.
Hence, compound semiconductor light-emitting devices must have separate amplification circuits and/or switching circuits externally installed.
Such external installing of a separate amplification circuit on a light-emitting device impedes high-speed switching due to the parasitic effect of the reactance or capacitance of external power lines.
Also, when compound semiconductor light-emitting devices are formed in an array and the array is to be used as a display device, a switching circuit must be externally installed so that light emission occurs at individual pixels. In this case, it is difficult to control the turn-on and turn-off periods of current on a pixel-by-pixel basis. As a result, controlling light-emitting duration is difficult.
To solve the above-described problems, it is an object of the present invention to provide a silicon light-emitting device that is formed on a substrate based on silicon and includes a transistor of at least one step to serve as an amplification circuit and/or switching circuit, and a display device adopting the silicon light-emitting device.
To achieve the above object, the present invention provides a silicon light-emitting device having an n- or p-type substrate, a doped region, a plurality of semiconductor material portions, and first, second, and third electrodes. The n- or p-type substrate is based on silicon. The doped region is ultra-shallowly doped, on one side of the substrate, with the opposite type dopant to the type of the substrate. The plurality of semiconductor material portions at least partially form a stack along with the doped region on the other side of the substrate. The first electrode is electrically connected to the doped region. The second electrode is electrically connected to a first semiconductor material portion, when a semiconductor material portion located at the outmost of the stack is referred to the first semiconductor material portion, and a semiconductor material portion adjacent to the inner side of the first semiconductor material portion is referred to as a second semiconductor material portion. The third electrode is electrically connected to the second semiconductor material portion. Here, a semiconductor material portion adjacent to the substrate is formed in the opposite type to the type of the substrate, and adjacent semiconductor material portions are formed in opposite types, so that a transistor having at least two steps is formed.
Preferably, either the first or second electrode serves as a cathode and the other as an anode, and the third electrode serves as a gate.
The silicon light-emitting device further includes an insulating film formed on some area of the second semiconductor material portion, and a high resistance material layer formed on the insulating film and the second semiconductor material portion, the high resistance material layer on which the third electrode is formed. The third electrode is electrically connected through the high resistance material layer to a narrow area of the second semiconductor material portion defined by the insulating film.
The plurality of semiconductor material portions are formed by injecting a dopant into the other side of the substrate deeper than the doped region.
To achieve the above object, the present invention also provides a silicon light-emitting device including an n- or p-type substrate based on silicon; a doped region ultra-shallowly doped with the opposite type dopant to the type of the substrate on one side of the substrate; a semiconductor material portion formed of the opposite type to the type of the substrate on the other side of the substrate; a first electrode electrically connected to the doped region; a second electrode electrically connected to the semiconductor material portion; and a third electrode electrically connected to the substrate. Accordingly, a transistor having a single step is included in the silicon light-emitting device.
To achieve the above object, the present invention also provides a display device having at least one silicon light-emitting device. In the silicon light-emitting device, an n- or p-type substrate is based on silicon. A doped region is ultra-shallowly doped with the opposite type dopant to the type of the substrate on one side of the substrate. A plurality of semiconductor material portions at least partially form a stack along with the doped region on the other side of the substrate. A first electrode is electrically connected to the doped region. A second electrode is electrically connected to a first semiconductor material portion, when a semiconductor material portion located at the outmost of the stack is referred to the first semiconductor material portion, and a semiconductor material portion adjacent to the inner side of the first semiconductor material portion is referred to as a second semiconductor material portion. A third electrode is electrically connected to the second semiconductor material portion. In this structure, a semiconductor material portion adjacent to the substrate is formed in the opposite type to the type of the substrate, adjacent semiconductor material portions are formed in opposite types. Accordingly, each of the silicon light-emitting devices includes a transistor having at least two steps.
To achieve the above object, the present invention also provides a display device having at least one silicon light-emitting device, the silicon light-emitting device including: an n- or p-type substrate based on silicon; a doped region ultra-shallowly doped with the opposite type dopant to the type of the substrate on one side of the substrate; a semiconductor material portion formed in the opposite type to the type of the substrate on the other side of the substrate; a first electrode electrically connected to the doped region; a second electrode electrically connected to the semiconductor material portion; and a third electrode electrically connected to the substrate. Accordingly, each of the silicon light-emitting devices includes a transistor of a single step.